US872829A - Electric-circuit controller. - Google Patents

Description

No. 872,829. PATENTED DEC. 3, 1907. H. W. LEONARD.

ELECTRIC CIRCUIT CONTROLLER.

APPLICATION FILED JUNE 1, 1903. RENEWED JUNE 3, 1907.

3 SHEETS-SHEHT 1.

W/ TNESSES: INVENTO/Y No. 872,829. PATENTED DEC. 3, 1907.

H. W. LEONARD. v ELECTRIC CIRCUIT CONTROLLER.

APPLICATION FILED mm: 1, 190a. RENEWED JUNE 3, 1907.

' 3SHBETSSHBHT 2.

W/T/VESSES: lNVE/VTOR No. 872,829. PATENTED DEC. a, 1907. H. w. LEONARD! ELECTRIC CIRCUIT CONTROLLER.

APPLICATION IiLED JUNE 1, 1903. RENEWED JUNE 3, 1907.

3 SHEETSSHE1T 3v WI THE SSE S:

HARRY WARD LEONARD, OF BRONXVILLE,v NEW YORK.

ELECTRIC-CIRCUIT CONTROLLER.

Specification of Letters Patent.

Patented Dec. 3, 1907.

Application filed June 1,1903 Serial No. 159.528. Renewed June 3.1907. Serial No. 877,046.

To all whom it may concern:

Be it known that Lflannr WARD LEON- ARD, a' citizen of the United States, residing at Bronxville, in the county of Westchester and State of New York, have invented a certain new and useful Improvement in Electrio-Circuit Controllers, of which the following is a specification.

My invention relates to devices such as are employed to cause the automatic release of provide in my preferred form a mechanical locking device for hoi ling the switch or rheostat lever in the desired operative position against spring or other tension, while the circuit to be controlled or a controlling circuit remains normal. This switch or rheostat lever is released to affect the circuit to be controlled when the condition of the circuit becomes abnormal and'th', release is effected by an electro-res onsive device which responds automatical y to abnormal changes in a circuit. sive device preferably consists of. a solenoid having a vertically movi arranged to trip the latch. The core of the solenoid in the preferred arrangement is normally held up against gravity by the magnetism, and u on the occurrence of no Voltage or under oad the core will drop and trip the latch. In other forms the core may be held down by magnetism against spring pressure and upon the occurrence of abnormal conditions in the circuit the magnetism will fail to hold the core whereupon the core will be driven upward to trip the latch. These arrangements may be combined with automatic overload switches, employed in conjunction with a rheostat. In certain forms of the underload electro-responsive device, the core is moved to its normal operative position upward, against gravity or in some direction against spring or equivalent pressure during the initial movement of the rlicostat or switch lever.

This electro-responcore which is v ma This movement a of the core may be accomplished in several ways, either mechanically or electrically, and the object of this movement is to permit the latch to return to the locking position and insome instances to place the core in position to instantly trip the latch, even efore the operator releases the switch, should the circuit become abnormal during the operation of the switch.

Other features of construction will be more fully described hereinafter.

One of the principal applications of my invention is to the no voltage automatic release of a motor starting rheostat, and consequently I will illustrate and describe my invention as applied to such an apparatus Heretofore in motor starting rheostats equipped with an automatic underload release, such automatic device was in the form of a magnet the keeper o'f which is attached to the switch arm. This form of automatic release depends upon the magnetism of the magnet to hold the keeper and arm against the action of a spring, so that when the magnetism of this magnet fails the keeper is released and the spring moves the lever automatically to the desired position. There are several objectionable features to such an arrangement, which objectionable features I am able to avoid by my invention. First. The magnetic pull of such a magnet depends very largely uponthe perfection of magnetic contact of the keeper. If the keeper be nicely fitted the residual magnetism is quite strong so that fre uently the automatic release fails to act w on it should do so u on the failure of current because the resi ual magnetism and the friction of the switch lever 'on the contacts are too great for the spring to overcome them. This residual magnetism is especially troublesome when the holding magnet is in the field circuit of a motor and the-armature and field are ke t in a closed circuit, for in such a case t e gradual slowing down of the motor causes an extremely slow and gradual decrease of the current in the magnet to Zero, whicl1 makes the residual magnetism quite considerable in amount. To overcome this residual magnetism it becomes necessary to use a very high grade expensive quality of iron in the magnetic circuit of the magnet and also to e a slight magnetic gap where the keeper makes mechanical contact with the poles of the magnet. This is frequently done by copper plating or tinning this surface to a sufii- 1 a magnet which is smaller, cheaper, and in c1ent extent to create the desirable magnetic every way better andmore reliable than the gap. But any slight variation in this magnetic gap makes a great difference in the magnetic pull and the amount ofv residual magnetism. Furthermore such a construction makes it impracticable to use as strong a spring as is often desirable, on account of the size, cost, and energy required for a magnet sufficiently strong to positively hold the arm against the stronger spring. Furthermore, it is sometimes desired to have this magnet in series with the shunt field winding of the motorand here again another difii-' culty is met with as the currentin the shunt field winding of a motor of a certain definite 'voltage andhorsepower, is variable over an extremely wide range depending upon the particular make. In common practice this variation would have a range of from 1 to 4. Hence with the construction described, the magnetic pull would vary over a very wide range and the maker of such motor-starters with automatic release cannot tell in advance what magnetic pull will be met with in practice and is obliged to make the magnet very much larger than really necessary in order to secure enough jampereturnsto get the re quired pull even with theminimu'm amperes met with in practice and yet the magnet must be wound with a wire sufficiently large so as not ,to'haveit overheat With a current say 4 times as much as the minimum. a

All of these difficulties I avoid by means of my invention. Instead of holding the spring actuated arm by meansof magnetism preferably produced by the shunt field-current of the vmotor, or other current I hold the arm in my preferred form by means of the mechanical latch. By the employment of a me-' .chanical latch, I am abletjo use as stiff a spring as desired, so that no'difiiculties arise due to the friction which the spring may have to overcome in moving the arm after thelatch is released.

The latch is released by means of a definite hammer blow dueto the movement ,of a certain mass under'the action of a constant force I ravity, although I may use a. ierform of force roducing despring or o vice instead ofgravity. I pre er however to use.'a freely .falling weight falling a definite distance and. therefore giving a predeter minable and constant blow to open thelatch when it operates. This weight is preferably in the formof a magnetic plunger which is normally held up by a magnetic pull and which falls when the current falls below a certain amount and delivers a blow to open the latch. As I only have to sustain by means of the magnetism a weight, the weight of which is very slight as'compared with the pull of the spring on the keeper in the former type, I can readily introduce a considerable air gap in my magnetic circuit and yet have I former type described above. ,For example, I find that 7 0 turns of a certain size wire are amply sufiicientfof the magnet in the field circuit when 350 turns are necessary in the former type, and of course the first cost,

space, and the energy required are proportionalto these figures. I The latch may be so designed that its benter of lgravity is so disposed relative to its at the action of gravity'tends to keep 1t in the locking position as shown in Fig. 2, or a light spring may be used tending constantly to eepit in that position, or the magnetic pull of the plunger may tend to kee the latch in that osition, or the shape of t e latch may be suc as to have it tend to remain in the locking position.

I prefer to h-ave'the solenoid iron-clad and closed at the top by iron, so that when the plunger is at the to of its movement the iron of the plunger is a mostlin contact with the iron of the solenoid, being preferably separated by a thin film of non-magnetic material,

sons to sufficiently reduce the residual magnetism' effect. v

The plunger can be raised by hand by the operator "ntil it reaches the top of its travel,

when it will be held by the magnetism, or it can beraised by a mechanical movement, or it canbe raisedmagnetically, or by any other desired means.

I prefer to raise the plunger by magnetism due to a separate winding of the solenoid of a sufficient number of turns in the main line circuit or the armature circult. Sometimes I place these plunger-raising turns in multiple with the resistance, of the starter or a portion 7 of it, so that this coil is energized strongly only while the current is passing through the starting resistance, and is practically cut out of'circuit when the arm is in its final or oper- I ing resistan'afid for a 5 ()0-volt starter across say l of the total resistance, so that I can use in this way a single kind of winding and resistance .tube for any commercial volt-age met withwThis connection enables me tov use a-very small Wire for this coilv and resistance as it is only subjected to its full duty for the few seconds of starting up the motor. SometimesIarran e the plunger/to be raised by' hand, and 't en to be held up by magnetism due to the shunt fieldcurrentora current due to an independent clrcuit across the line, and I arrange another plunger'so get no voltage and overload automatic proquarter of an inch in diameter.

tection with a single arm, a single latch and a very compact form of magnet windings.

hen the air gap is large the cross-section of the iron is not important, and by making the cross-section very small, economy in cost and size of both the lifting coil and the hold mg coil is effected. I therefore reduce the size of the plunger 1n practlce to about one- 1n a further advantage in that the density of the lines of force is increased at the magnetic holding surface which gives a better result for the same number of ampere turns. With this reduced lunger additional weight may be supplied t iereto exterior to the coil or at the bottom of the plunger. t

The invention is illustrated in the accompanying drawings, in which Figures 15 inclusive illustrate diagrammatically several forms of the invention as employed in connection with a shunt-wound electric motor; Fig. 6 is an elevation illustrating the switch mechanism mounted on the usual base; and Figs. 711 Einclusive are diagrams of various modifications;

Referring first to the mechanism shown in Fig. 6, A indicates the usual base of insulat ing material, carrying the resistance steps and circuit connections on its under side and the contact buttons a of the resistance steps die 6 and a sprin I) tending to return the arm to the initial or starting position. L designates a latch pivotally mounted on the base plate and provided with a tripping arm Z. The latch and tripping arm maybe so shaped and proportioned in weight that it will always assume the latching position when free, and such an arrangement will be suitable where the apparatus is designed to be placed vertically; but since the apparatus will not always be hung sufliciently accurate, or since it may be desired to place it in a horizontal position, I preferably provide the latch with a very light s ring Z" which tends to return the latch to t 1e locking position. Latch L engages a pin on arm. B to hold the arm in. its final position. S is an iron-clad solenoid having a freely moving core 8 which is attached to a rod 8 of non-magnetic mate'- rial having a head which engages the tri ping arm Z to trip the latch when the core rops. The rod .9 works through an adjustable iron bushing s screved into the top of the iron case of the solenoid. 'hen the core is in its uppermost position, it is in contact with the bushing 8 but a magnetic gap is provided This results 1 between the bushing and the core by means of a non-magnetic film s and which film serves to reduce the effect of residual magnetism on the core. The non-magnetic film as shown in the drawing is considerably exaggerated in thickness for the purpose of illustration. The parts as illustrated in Fig. 6 represent-the apparatus in its normal operative position, and it will be noted that when the current through the solenoid fails, or decreases abnormally, the magnetism will be insutlicient to hold the core in its elevated position, an hence the core will drop, and through the ead on rod 8 impart a blow to the tripping arm of the latch, thereby releasing the switch arm B and permitting the sprim b to return the switch arm to the initi or starting position. In this illustration no separate means is illustrated for raising the core to its operative position, but the so enoid coil might be wound so that it will produce suificient pull to raise the core when the circui v is closed at the initial movement of the contact arm. But with the arrangement illustrated it is generally preferable to raise the core by hand simultaneously with the forward movement of the contact arm, the magnetic pull being sullicient to hold the core in its elevated position. In practice, however, I refer to provide the solenoid with an ad itionalwinding of a sutiicient number of turns "to raise the core when the circuit 'is closed on the initial movement of the contact arm, "and such winding may be connected either in the main line or in the armature circuit. Instead of the additional winding, I may provide a mechanical'device such as an arm on the contact lever, whereby when thecontact arm is moving from the open circuit to the closed circuit position, the

sition to ermit the magnetic pull to hold the same or ift it further to its full-elevated position. Various arrangements for accomplishing the elevation of the core are illustrated in Figs. 1-5 inclusive in addition to other features.

Referring to 1, M represents a shunt wound electric motor connected across a circuit through a starting rheostat of the character illustrated in Fig. 6, but rovided with anadditione coil for raising t 1e core of the solenoid. In this arrangement Ris the raising coil which is connected between the final contact of the rheostat and the motor armature, and H is the holding coil connected between the first contact of the rheostat, and the motor field winding. It will be noted that the raising coil R is in series with the motor armature across the line, and that the holding coil H is in series with the hold wind ing across the line, and that the motor armature and field windings and the two coils are in a closed circuit. It will be understood that in moving switch arm B from the open core Will be held in a suflicientlyelevated po-- circuit position to the first resistance con-' tact, the current passing through coil R will produce a sufficient pull to move the core upward. When the magnetism due to the coils H and R fails, or decreases abnormally, the core will drop. and tripv the latch as above explained.

and the spring will drive the core upward,

which imparts a blow to the tripping arm I l and trips the latch.

I by a rod 8.

'ing arm B an In Fig. 3 the two windings are employed to. respond, respectively, to overload and underload, and the cores are raised to the operative position either by hand or by an arm on the rheostat switch, both arrangements being shown. --In this construction the underload coil 'U is placed above the overload coil 0, and the two cores are'carried This rod at the upper end may be provided with a disk or arm .9, placed in the path of arm B on switch B so that when the switch is in the initial or starting position said arm B will hold the cores in the elevated position so that the pull of coil U will hold the cores elevated as the s itch is moved toward the final osition. iiistead of employvated by hand by means ofra knob s at the In such case the operator will raise the cores with one hand as he starts switch B forward with the other hand. 'Thetri ping arm-Z of; the latch extends between t he'two cores in osition to be struck by the upper core when 0th cores descend: Under normal conditionstthepull of coil U will hold the cores elevated a ainst gyavity whereu gravity and against'the pull of coil, but

upon the occurrence of novoltage or an abnormal decrease of current, coil U will have insuflicient pull to hold the cores against onthey will fall and tricp the ch; Upon the occurrence of a pre etermined overload the pull of coil 0. will increase suificiently to overcome the pull of coil U, and the coreswill be drawn downward and trip the latch. It will thus be seen that by the provision of an extremely simple and compactdevice, "i. e, a single arm, a singlelatch, and every simple, cheap and no voltags and over-loadTre'lease in a most ef fective andfreliable mannerw The .circuit connections are the same as inIF igs. 1 and2.l

volt starter, I connect this plunger-raisingdisk 8 the cores may be elev I Instead of connecting the raising coil series with the motor armature as in Figs. 1 and 2, this coil may, if desired, be connected in multiple with the resistance of the starter,- tiple-with a portion of it, so that the or in mu coil is energized strongly only while current is assing through this starting resistancean is practically cut out of circuit when the arm is in its final or operating position. This arrangement is shown in F1 4. In such with a high resistance R in series with the coil, such as an enameled'pottery resistance tube of the character shown in my Patent For a two hundred and fifty coil R and resistance R across, say,-half of the total starting resistance, and for a five hundred volt starter across, say, one-quarter of the total resistance. In this way, I am enabled to utilize a single size or standard winding for coil R and resistance tube R for any desired voltage. Also this enables me to use a very small wire for the plungerraisingugioil and resistance, as it is subjected to its ing. which the motor is started and is definergized under normal operative conditions.

l duty-for only the few seconds dur- In Fig. 4, the holding coil H is'connected in I series with the motorfi'eld winding as in the other arrangements, and the operation in responding to abnormal conditions is also the same.

In Fig. 5, I havesh wn a construction inwhich the plunger is raised to operative position mec anically'. Here the switch-arm B is provided with an angular extension B, the pivotal point bein so arranged relatively e plunger that when the switch returns to its extreme inoperative position at the left the extension B will raise the plun erto the position in which it is illustrate When switch B is moved forward and the circuit closed, the plungerwill still be within coil H, and it will now be held b magnet sm as switch B is moved toward the final position. The holding coil H is here connected in series with the field winding of motor M as in the other arrangements, andthe release is affected in the same way.v

In Fig. 7 the circuit connections are differently arranged! ,x' lhe field winding of the motor is directly connected across the circuit terminals as shown or it may be connected through therheostat resistance. In either instance, however, the winding of the controlling coil is connected in a separate shunt across the line. arm B closes the circuit at the second contact, current will flow from the plus terminal throu h arm B and wire 1 to the raising coil R an holding coil Hand through resistance Thus when the rheostat- R to the other terminal. This current energizes the coils R and H and causes them to raise the core into operative position; As arm B is moved from the second contact toward the final position, the raising coil R is cut out of circuit, but the holding coil H remains in circuit the. current flowing through the rheostat resistance, extra resistance R wire 2 to the holding coil and through resistance R to the line. Thus it will be seen that the current through the coils which control the movement of the core, or in other words the release of the rheostat arm, is entirely independent of the current which energizes the motor field winding and of its armature winding. The latch L and tripping arm Z are substantially the same as in the other forms except that in this instance the latch is provided with a stop I which prevents the spring from throwing the latch beyond the locking position.

In Fig. 8 is shown an arrangement somewhat similar to that of Fig, 7 but in this instance the startin rheostat is provided with an automatic ovefload circuitbreaker. The rheostat switch, the latch, and controlling device are similar in construction to the corresponding parts in Fig. 7. O is the over: load switch which is pivoted on the same pin with switch B and a spring T tends to drive the two switches toward each other. Switch 0 is closed by the movement of switch B to its initial position said switch engaging cushioned stud 0 on switch 0 for that purpose, so that the circuit to motor armature can only be closed through the entire resistance. Switch 0 is held closed by a latch 0 and this latch is tripped by a blow from the core of solenoid O which responds to a predetermined overload. The overload coil and switch are connected in the armature circuit of motor M. Switch B and its controllim solenoid respond to abnormal underload The raising coil R of the underload device is connected between the first and second live contacts of therheostat in series with one step It of the rheostat resistance. hen the arm B is on the first live contact, the current flows from the plus side through coil 0. switch 0, arm B, coil R, resistance R and then divides following in one path through the rest of the starting resistance and the motor armature, and 1 in another path through coil ll and the motor shunt field winding. When switch B- is moved to the second contact, coil R and resistance R are cut out of circuit. When a definite overload oceurscoil 0 will raise its core against gravity causing it to impart a blow to latch 0, thus tripplng the same and releasing switch 0 which, under the tension of the spring T, opens and breaks the entire circuit. To close switch 0 again switch B must be brought back to the initial position, said movement carrying switch 0 to its closed position.

When an underload occurs the pull produced by coil H will be insufficient to hold its core against gravity and said core will drop and impart a blow to the tripping arm of latch L, thus releasing switch B which, under the tension of the spring T, returns to its initial or open circuit position. WVhen switch B responds to underload, switch 0 remains closed.

In Fig. 9 an arrangement similar to Fi 8 is illustrated, but the overload solenoid is provided with an additional winding 0, whereby the overload switch 0 is caused to open when switch B is brought back to the initial position, both under normal and abnormal conditions. In addition to this feature the overload switch is provided with an auxiliary switch 0 on which the circuit is finally broken as is now well understood in the art. Switch 0 is closed by switch B. through studo as in Fi 8. When switch B is moved forward to t e first live contact, current flows from the plus terminal through overload coil 0, switch 0, switch B, wire 1, through coil 0 and wire 2, throu h raising coil R and holding coil H, and the eld windin of motor M to the other terminal. It wi 1 be noted that at this pointboth coils O and 0 will be ener ized, and the pull of these coils under normal conditions will be sufficient to raise the core against gravity and effect the release of switch 0 the moment the circuit is closed by switch B. To avoid this the operator will hold this core against the pull of coils O and O and for this purose the core is provided with a handle 0 Vhen switch B is moved to the second live contact coil 0 is cut out and the operator may release the overload core. This movement of switch B also cuts the raising coil out of circuit, and the current from switch B will now flow throu h resistance R wire 3, holding coil H and the field winding of motor M. The motor armature connection will be as usual and when switch B is in its final position, the connections will be as follows: From the plus terminal, the current will flow through overload coil 0, switch, O and switch B to the final contact of the rheostat from this point the current divides, one circuit being direct to the motor armature, and the other through the rheostat resistance, including resistance R, conductor 3, holding coil H and the motor field winding. \Vhen an underload occurs the core of the underload. device will drop and effect the release of switch B, and when a predetermined overload occurs the pull of coil 0 will increase sufficiently to raise its core and effect the release of switch 0. As before stated when the overload switch operates, the underload switch must be brought back to its initial position before the apparatus can be pro erly reset in its operative position. It wil be noted that should the operator return switch B to the first live contact after having passed In Fi 10 is shown an overload switch 0 and 0? like that in Fig. 9, but the latch which holds it closed is arranged to-be controlled by both electro-res onsive devices, and hence no automatic re case is necessary for switch B. "The overloadcoil O is connected between the plus terminal and the stationary contact of switch 0, and its core is arran ed the vided with a raising coil R and a holding coil to strike a tripping arm on the latch. he underload device is located adjacentito the overload device and its core is arranged to engage an extension of the .tripping arm of atch. The underload device is pro-.

H; the former is connected between the first live contact of the rheostat and the motor field winding by wires 1 and 3, and the latter is connected between the second live contact and the motor field winding by the wires 2 and 3 and in series with extra resistance R It will be noted that as switch B moves from the first to thesecond contact,'coil R iscut .out of circuit, and that resistance R remains in series with coil H, the rheostat resistance, and the field winding when switch B is in its final operative position. The operation of the two electro-responsive is-the same as before except that sw1tch'O. only is affected.

In Fig. 11, is illustrated an overload and underload circuitbreaker combined with a motor-starter or speed controller, and connected so that there will be no open circuit tion is omitted in this figure.

' switch is bro controlling switch will be opened; In this I arrangement rheostat switch B is preferably position atthe rheostat, and the overload device is provided with an additional windmg as in ig. 9, whereby, when the rheostat ht to its initial position, the

not spring .actuated. S is a controlling switch held closed against spring tension by a latch similar to latch L in the other illustrati'ons, but which for simplicity of illustra- This latch; of this switch is tripped by two tripping arms or levers s and a, and these arms are arranged to be actuated by a blow from the cores of overload coil 0 and underload coils U, respectively. The overload coil is connected between the plus .terminal and upper stationary contact of switch S, and from the lower stationary cont-act of that switch a connection extends to rheostat switch B. The armature of motor M is connected between the final contact ofthe rheostatand t will thus be seen that the other line terminal. The underload coil U is connected between the first rheo- =stat contact. and the field winding of themotor, so that those two windings will be in series across the line. O is the additional coil of the overload device, and this coil is connected between the first and second rheostat contacts. When the circuit is closed at the first contact, the pull of this coil is sufficient to raise the core of the overload device and effect .therelease of switch S-because it is'then-in series with the motor armature, but since coil 0 is provided only for the purpose of opening swltch-S when switch B is returned to its initial p'os1t1on,

- it is necessary to hold the overload core until switch B in: starting is moved beyond the first contact, whereupon its/pull" under normalconditions will be insuflicient to raise the core. The operator may then release When switch B is returned to the the core. V first contact, the 001i 0 will raise its core and actuate arm s and release switch S. Inv

starting, switch S is closed, while switchB is on the initial contact'of the rheostat and the plunger. of coil 0 is held down by the operator. This closes the circuit through coil 0, switches S and B, .coil U and the motor field winding one branch, and

through coil 0, switches S and B, coil rheostat resistance, and the motor armature in another branch. When the arm B is moved to the second contact, the armature current no longer passes through coil and. hence the operator can release the plunger of coil'O. The current then passes in onepath'through ooilsO, U, and themotor field winding in series, and through the rheostat resistance and motor armature in another path. If an underload occurs, coil U will respond, and its core will drop and eifect the openin of switch S. If an overload occurs, coil will respond and raise its:

core and efl'ect'the opening of switch S.

When the operator returns switch B, coil 0 will be fully energized when the switch reaches the first contact, and-hence that coil will raise the core of the overload device, and actuate arm 8 and effect the release of switchS. By reference to Fig. 11, itwillbe. I

seen that there is no open circuit in the,

rheostat, e. 'i.,-the circuit through the'motor field and armature is always closed throu h the rheostatresistance, and coils U and( By this arrangement, the rheostat contacts.

are not injured by sparks, and the breaking of the circuit is done by an independent 7 rapid action switch.

While I have shown and described various forms of my-invention, it will be understood that the invention is capable of embodiment in other forms of construction and I do not wish to be limited in the scope thereof except as indicated by the following claims.

What I claim is:

1. The combination with a switch, of a mechanical device for holding it in a definite position, an electromagnetic device having a movable part held by said electro-inagnetic device against the action of a force tending tomove it whereby when the magnetism of said electro-inagnetic device falls below a certain strength, the said movable part will move under the action of said force and deliver a blow and cause the release of said mechanical holding device, and auxiliary means for moving said movable part to its normal operating position.

3. The combination with a switch, of a mechanical device for holding it in a definite position, an electro-inagnetic device having a movable part held by said electro-magnetic device against the action of a force tending to move it whereby when the magnetism of said electro-magnetic device falls below a certain strength, the said movable part will move under the action of said force and deliver a blow and causethe release of said mechanical holding device, auxiliary means for moving said movable part to its normal operating position, and means for protecting the'circuit against overload conditions.

3. The combination with a switch lever, of mechanical device for holding it in a definite position, an electro-magnefic device having a movable part held by said electro-magnetic device against an action of a force tending to move it whereby when the current which energizes said electro-magnctic device falls below a certain strength, the said movable part will move under the action of said force and deliver a blow and cause the release of said mechanical holding device, and auxiliary means acting only while the switch lever is in a position other than its normal operating position for moving said movable part toit 1 held position.

4. The combination with an electric niotor, of a circuit controlling switch, means for moving said switch, mechanical restraining means for holding said switch, an automatic device having a movable part normally restrained by magnetism and which automatically operates when the electroinotive force oi the circuit falls below a certain amount to release said mechanical restraining means and. permit the movement of said switch by its actuating means, and auxiliary means controlled by said switch for placing the said movable part in its normally restrained position.

5. The combinationof a circuit controlling switch, means tending to move said switch, mechanical restraining means for holding the switch in. a certain position, an electro-inagnctic device having a magnetic ma s normally held up against the action of gav tions of the circuit falls and delivers ablow to cause the release of said restraining means, i and automatic means controlled by the movement of said switch for raising said magnetic mass to its'elevated position.

6. The combination of a circuit controlling device, means controlled by said device for moving a magnetic mass against a continually acting force, an electro-magnetic' device which normally holds said magnetic mass against the action of said force, and means whereby upon the abnormal diminution of the magnetism said magnetic mass delivers a blow resulting in the movement of said circuit controlling device.

;7. The combination of a circuit controlling switch which tends to move in one direction, a mechanical restraining device for holding said switch in a certain position, an electromagnetic device having a movable part for releasing said mechanical restraining device under abnormal conditions of the circuit, and auxiliary means controlled by said switch for placing the movable part of said electro-magnetic device in operative position.

8. The combination of a circuit controlling switch, mechanical restraining means for holding said switch in a fixed position, an electro-magnetic device responsive to abnormal'conditions in the circuit for releasing said mechanical restraining means, and auxiliary means controlled by said switch for placing the movable part of said electromagnetic device in operative position.

9. The combination with a circuit controlling switch, mechanical restraining means for holding said switch in a fixed position, an electro-magnetic device responsive to abnormal conditions of the circuit for releasing said mechanical restraining means, the 'movable part of said electro-magntic device being subjected to a continually acting force in one direction, and auxiliary means for moving said movable part against said continually acting force to place the samein operative position.

10. The combination of a circuit controlling switch, mechanical restraining means for holding said switch in a fixed position, an electro-magnetic device responsive to abnormal conditions of the circuit for releasing said mechanical restraining means, the movable part of said electro-magnetic device being operated by gravity, and auxiliary means controlled. by said switch for moving said movable part against the force of grav ity to place the same in operative position.

11. The combination with a circuit con trolling switch, mechanical restraining means for holding said switch in a fixed position, an clcctroinagnetic device having two wii'idings and a vertically movable mass, said mass being adapted to fall and release ity, and which under abnormal condii said mechanh'al restraining means upon change of current in one of said windings, the other of said windings raisingsaidpmass initially.

Q i 12. The combination of a supply circuit of a motor, a starting rheostat for said motor,

mechanical restraining means for holding the arm of said rheostat in running osition, a solenoid having two windings an avertically movable core, said core being adapted to fall and release said mechanical restraining means, one of said windings being temtroller, of.restraining means for holding a movable element therec in a fixed position, an electro-magnetic device having two windings and a vertically movable element, said element being adapted to fall and release said restraining means upon change of current in one of said windings, the other of said windings raisin said element initially.

14. The comination of an electric circuit controller, mechanical restraining means normally holding said controller in a certain position against a constantly acting force, a magneticmass adapted to move from its normal'position and release said restrainin means, auxiliary means. for moving sai mass to its operative position during the operation of moving the controller to its restrained position, and an electro-magnetic winding responsive to the volt e onthecircuit which under conditions of a normal voltage causes the movement of said magnetic mass to release said restraining means.

15. The combination of a resistance con-. trolling device, restraining means for holding said device in a fixed position against a constantly 'acting force, a magnetic mass which by its movement releases said re straining means and thereby effects the movement of said device to insert a rotect-' ive resistance, means for automatica y moving said mass'to its operative position, and magnetic means for retaining said mass iii-its operative position. l

16. The combination of a spring actuated switch, mechanical restraining means therefor, a magnetic mass whichfalls under the action of gravity to release said restraining means upon abnormal conditions of the circuit, means for magnetically and automatically raising said mass to its operative position and for retaining said mass in its operative position whereby the electric energy required for holding said mass in its operative position is materially less than the electric energy employed to raise said mass.

17. The combination of a hand operated circuit controller adapted to be restrained in a certain position, a magnetic mass func-,

tionally related to the said controller, electro-magnetic means. for retaining sald mass in its normal position against the action of a force, and means operative only when said circuit controller is in adifferent position for moving said mass to its normal positlon.

18. The combination of a circuit controller, mechanical restraining means for holding only when said-circuit controller is in a fposition other than itsnormally restrained position wherebvthe said mass is moved to" its normal position.

19-. The combination of an electric motor, a protective device automatically responding to 'oen the'circuit' upon the occurrence vice responding to automatically open the circuit ipo'n the occurrence of a dliierent abnormal condition, a circuit controller functtionally related to at least one of said protective devices, and auxiliary means con- 1 trolled by said circuit controller for setting one of sa d'protective devices when said con troller-is placed in a certain position other than its normal operating position 20.. The combination of a circuit controller, an elc'ctro-res onsive device responsive to minimum con 'tions, an electro-respon-- sive device res onsive to maximum condi tions, and sum iary means for moving the movable elementof one of said 'electroresponsive devices to its normal against aconstantly acting force, sai means being dependent upon the position of said circuit controller when the latter is in a position other than its normal operative, position.

osition 21. The combination of a circuit controller' .having a movable element for varying a re- 'sistance, said element being adapted to be restrained in a certain position, an electroe' responsive device having an inde endently movable ma netic mass functiona y related to the said e ement to effect the o ening of the circuit by the movement of said element, and means operative onlywhen said controller is in a position other than its normal operative position for moving said mass against a constantly acting force.

22. The combination of an electric motor, two movable circuit controlling elements in series with each other and with the armature of said motor, one of said elements being a resistance controlling element for starting said motor and the other of said elements beingan automatic switch responsive to overload current for opening the circuit of the motor armature, and means comprising a movable device and two electrores onsive 85 of one a normal condition, a protective deance controllingclement, one of said wind ings being responsive to 110-voltage .to control the automatic movement of said resistance controlling element to its initial position and the other of said windings being energized for moving-said movable device when starting the motor and denergized when the motor has attained normal speed.

23. The combination of aniotor, a resistance having a hand operated movable device for varying the amount of resistance in circuit and adapted to be restrained in the resistance all out position, a magnetic mass functionally related to said device, electromagnetic means for retaining said mass in a position against the action of a force, and means for moving said mass to its operative position during the operation ofmoving said device to its restrained. position,

24. The combination of a motor, a resistance having a hand operated movable device for varying the amount of resistance in circuit and adapted to be restrained in the resistance all out position, a magnetic mass functionally related to said device, electromagnetic means for retaining said mass in a position against the action of a force, and GlOGtIO-lflilgHGiliG means for moving said mass to its operative position, said latter electromagnetic means being operative only while said device is'bcing moved to its restrained position.

25. The combination of a motor, a resistance having amovable device for varying the amount of resistance'in circuit and adapted to be restrained in the resistance all out osition, a magnetic mass functionally reihted to said device, electro-magnetic means for retaining said mass in a position against the action ofa force, means operative only when said device is in a position other than its resistance all out position for moving said mass against the action of said force, and an overload device, saidmovable device and said overload device being functionally related protectively.

26. The combination of a motor, a resistance having a movable device for varying the amount of resistance in circuit and ad apted to be restrained in the resistance all out position, a magnetic mass functionally reated to said device, electro-niagneticmeans' for restraining said mass in a position against the amount of resistance in circuit and adapted to be restrained in the resistance all out position, a magnetic mass functionally related to said device, electro-magnetic; means for restraining said mass in a position against the action of a force, means operative only when said device is in a position other than its resistance all out position for moving said mass against the action of said force, an over-.

load switch, said switch being ada ted to be closed mechanically by said mova le device when the latter is in its off position.

28. The combination of a hand operated electric controlling device, a magnetic mass for winding for moving said mass to said position, said second winding being denergized after acting to move said mass.

29. The combination of a 'rheostat having .a movable element for varying the resistance an automatic magnetic circuit-breaker, said circuit-breaker compris ngtwo electromagnet windings acting upon a common mass,

one of said windings being responsive to overload current and thereby control the circuit breaker and the other of said wind: ings being responsive to control the circuitbreaker when said element is in a certain position. I i

3Q. The combination with a circuit-controller', of restraining means for holding a movable element thereof in a fixed position,

an electromagnetic device having two windings and a movable element, said element being adapted to move and release said restraining means upon change of current in one 0 said windings, the other of said windings acting to move said element to its restrained position initially.

31. The combination of an electric motor, I

two switches in series with each other and with the armature of said motor, means for insuring the establishment of the circuit by one of said switches, means for insuring the automatic breaking of the circuit by the other of said switches upon movement of said first named switch, and means for automatic ally controllingthe movement of said first named switch.

' 32. The combination of an electric motor,

two switches in series with each other and with the armature of said motor, and means functionally relating said switches for insur ing that the circuit will be com leted at one of said switches and automatica ly opened at the other of said switches upon movement of said first named switch.

33. The combination of an electric motor, arcsistance controlling, circuit closing switch for establishing the current, and means functionally related to said switch and controlled by said switch for insuring the interruption ing said mass, said second Winding heing-con-- trolled b said element and denergized 15 when sai element is in final position, and an overload protective switch for automatically opening the circuit u on the occurrence of overload current, an means controlled by said element for effecting the opening of said 20 switch when said element is moved towards v its initial position. e

This specification signed and witnessed this 27th day ofMay, 1903.

. H. WARD LEONARD. VVitness'es:

CAROLYNAG. LEONARD, LEONARD KEBLER.

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